A beam of light has an electric field intensity of 200 Vm Ca

A beam of light has an electric field intensity of 200 V/m. Calculate the magnetic field intensity, B. Calculate the energy density and the light intensity of the beam. Calculate the momentum flux (momentum per second) the light beam carries past a fixed point.

Solution

Here

electric field , E = 200 V/m

a)

magnetic field intensity = E/c

magnetic field intensity = 200/( 3 *10^8) T

magnetic field intensity = 6.67 *10^-7 T

b)

energy density of beam = 0.5 * E^2/(c * u0)

energy density of beam = 0.5 * 200^2/(3 *10^9 * 4pi * 10^-7)

energy density of beam = 5.305 W/m^2

the energy density of beam is 5.305 W/m^2

c)

momentum per second passing = energy density/c

momentum per second passing = 5.305/(3 *10^8)

momentum per second passing = 1.768 *10^-8 Kg.m/s